Window ventilator and silencer



Dec. 12, 1933. R. B. BOURNE V 1,933,800

WINDOW VENTILATOR AND SILENCER Filed March 18, 1931 2 Sheets-Sheet lINVENTOR. Rom/v0 B. 500R -15 Y B W 2 M A TORXEYS.

Dec. 12, 1933. R. BJBOURNE WINDOW VENTILATOR AND SILENCER Filed March18, 1931 2 Sheets-Sheet 2 INVENTOR. Rom/v0 B. BlN/RNE M TTORNEYS.

Patented necyiz, 1933 This invention relates to devices for ventilatingrooms through a window opening and having means for excluding street andother noises which would otherwise be admitted to the room.

In devices of this character, the size of the opening is an importantfactor. One of the problems presented is that of handling a maximumamount of air without turbulence while at the same time providing in the,air passageways sound attenuating means effective to prevent sounds of.even very lowfrequencies from entering the room. The motor andfan mustbe capable, of moving a relatively large'volume of air withoutthemselves creating suflicient noise to be audible within the room. Theattenuating means must perform, its function with minimum obstruction tothe passage of the air. In-general it is the object of the presentinvention to secure a more economical attenuation of street noises,particularly those of low frequencies,- in other words, to securemaximum noise elimination with a minimum sacrifice of ventilatingefficiency. The attenuation of sound waves by means of acousticfrictionfalls off as the frequency is lowered; but in the structure of thepresent invention low frequency sounds, such as are. made by automobileexhausts, rumbling of trolley cars and the like, are sufllcientlyattenuated by providing relatively long passageways, so curved 'as toincrease their sound attenuating ability. One feature of the presentinvention is the use of long, obstructionless and easy-curvingpassageways. More specific features of the invention will be apparentfrom the following specification and claims.

In the accompanying one embodiment of the invention:

Fig. 1 is aperspective view with parts cut away; 3

Fig. 2 is a top plan view with the cover plate removed; H Fig. 3 is afront elevation of the device; and

Fig. 4 is a sectional view substantially on line 4-4 of Fig. 1. j I

Referring to the drawings, 1 designates a flat substantially rectangularcasing provided with straight vertical partitions 2, 3, 4 and 5. As bestshown in Fig. 2, the end wall 6 of the casing is curved at 7 andpartition 3 is connected thereto by a curved partition 8 forming acontinuation of curve ,7. Similarly, opposite end wall 9 of the casingiscurved at 10, and a curved partition 11 connects portion 4 with thecurved semi-circles with the free ends of partitions 2- drawings whichillustrate portion 10.. Curved walls '1, 8 and 10, 11 form- 1,93s,s i

UNITED STATES PATENT OFFICE 1,938,800 wmnow. vrm' rma'roa AND SILENCERRoland B. Bourne, Hartford, Coma, assignor to The Maxim SilencerCompany, Hartford, Conn., a corporation of Connecticut Application March18,1931. Serial No. 523,541- Claims. (01. 913-94) and 5, respectively,as their centers. Partitions 2 and 5 are connected by a portion formedwith two semicircular curves l4 and having their respective centers atthe free ends of partitions 3 and 4. Point 16, at which curves 14 and15- meet, is positioned centrally of passageway 1'] formed by partitions3 and 4, and passageway 1'7 is twice the width of passages 18 and 19.

Passages 18 and 19 terminate respectively in openings 22 and 21 formedin the upper face of casing 1 at the inner corners thereof. Each opening22 and 21 is provided with a shutter arrangement (see Fig. 4).comprising a frame 23 provided with a plurality of curved shutter vanes24 pivoted to frame 23 by means of pins 25. The free ends of the shuttervanes are connected together for simultaneous movement'by a link 26. Themovement and position of the shutters are controlled by a handle 2'7positioned exteriorly of casing 1 and connected to one of the pins 25.It will be seen that with the shutter vanes fully open, as in thedotted-line position of Fig. 4, the air streamis directed upwardly andtoward the window 28, thus substantially eliminating objectionabledrafts when the device is blowing air into the room in cold weather. Anintermediate position' of handle 2'7 will place the shutter vanes insuch position that the air be directed inwardly away from the windowshould this condition be desirable, Upwardly curving members 29 directthe air current in the passages to theshuttered openings.

The inner surfaces of the casing and the faces of the partitions formingthey air passages are covered, as indicated at 30,.-.with soundattenuating material, preferably a high grade acoustic felt covered witha perforated oil cloth.

A circular opening 31, defined by a short cylindrical ring 32, is formedin the outer wall 33 of I the casing 1 and opens centrally of passage17. Ring 32 is of larger diameter than the vertical depth of casing 1and is connected to the top and bottom faces of the casing by conicalsections 34.

A reversible electric motor 36 is positioned in the casing between theconical sections 34 and is provided with a light weight propeller typefan 35 spring mounted on the motor shaft and positioned within ring 32.The motor 36 is carried on a stiff radial flat spring mounting system37. This mounting satisfactorily takes care of all ex cept certain highfrequency noises which pass through it, due probably to the fact thatthe vibration at these frequencies is not entirely torsional. Thismounting, however, gives great rigidity in all other directions.

The slip stream from a propeller type fan is helical in nature butturbulence from this cause is prevented by the provision of double widthpassage 17 which forms a straight passageway immediately behind the fanample to give the air stream an opportunity to become more or lessuniform before entering any of the curved passages.

By the arrangement above described, the large volume of air enteringpassage 1'7 is diverted in equal shares to the long obstructionless easycurving passages 18 and 19, resulting in an eificiently silencedventilator characterized by an exceptionally high air economy. Moreover,by this arrangement a compact symmetrical structure is obtained, andsince the fan and motor are located outside the window any slight noisearising at this point, incidental to the moving of air or in the motor,is easily attenuated in the passageways.

The central switch assembly 40, by which the motor may be started,stopped or reversed, is supported on the inside wall 41 of the casing.The connection wires 42 leading from the switch to the motor areseparated into two sections by the plug connection 43,thus permittingthe motor to be withdrawn through opening 31 without disturbing thefixed wiring of the switches. A flexible cord conductor 44 extendingfrom the switch assembly .outwardly of the casing is provided with aplug 45 for insertion in any convenient outlet.

The top and bottom of casing 1 are provided respectively with sealingstrips 50 and 51, and the sides with brackets 52 and 53, whereby aweather and sound proof joint may be effected with the sash, sill andside frames of the window opening. What I claim is: v

1. A silencing ventilator for windows which comprises a casing adaptedto be positioned between a window and its sill and having an openingoutside the window, a straight sound attenuating passageway directedinwardly from said opening and two tortuous, unobstructed, easycurving,sound-attenuating passageways leading from said straight passageway andterminating in independent openings inside of the window. 2. A silencingventilator for windows which comprises a casing adapted to be positionedbeating passageway directed inwardly from said I of the casing oppositesaid first named opening.

tween a window and its sill and having an opening outside the window, astraight sound-attenuating passageway directed inwardly from saidopening, and two tortuous, unobstructed, easycurving, sound-attenuatingpassageways leading from said straight passageway and terminating inindependent openings inside of the windows, said straight passagewayhaving a cross-sectional area equal to the combined cross-sectionalareas of said two tortuous passageways.

3. A silencing ventilator for windows which comprises a casing adaptedto be positioned between a window and its sill and having an openingoutside the window, a straight sound attenuopening, two tortuous,unobstructed, easy-curving, sound-attenuating passageways leading fromsaid straight passageway and terminating in independent openings insideof the window, and means in each of said last named openings to controlthe direction of the air currents issuing therefrom.

4. A silencing ventilator for windows which comprises a casing adaptedto be positioned between a window and its sill and having an openingoutside the window, a sound-attenuating passageway directed inwardlyfrom, and in alignment with, said opening, a plurality of tortuous,unobstructed, easy-curving passageways leading from said first namedpassageway and terminating in independent openings inside 'of thewindow, said first named passageway having a crosssectional areasubstantially equal to the combined cross-sectional areas of said lastnamed passages.

5. A silencing ventilator for windows which comprises a flat generallyrectangular casing adapted to be placed horizontally between a windowand its sill and having an opening positioned centrally of one edge faceof the casing, a sound attenuating passageway formed within the casingand communicating at one end with said opening and at its other end withtwo diverging, tortuous, unobstructed, easy-curving passageways, saidlast named passageways terminating in independ ent openings formed inthe upper face of the casing at the corners thereof adjacent the edgeface ROLAND B. BOURNE.

